Single reel tape cartridge having guide surface

ABSTRACT

In one example of one aspect of the invention, a single reel data storage cartridge is provided. The single reel data storage cartridge includes a housing having an access window and a reel rotatably disposed within the housing and having storage tape wound on the reel. A guide surface is further disposed within the housing such that the tape extends from the reel to the guide surface before extending to the access window. The guide surface thereby increases the tape path from the reel to guiding elements within a tape drive to reduce the force imparted on the tape edge during guiding.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of prior application U.S. Ser. No.10/627,371, filed Jul. 24, 2003, the disclosure of which is hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to storage devices housing magneticstorage media, and more specifically to single reel cartridges forhousing magnetic storage tape and having one or more guide surfacestherein.

2. Description of the Related Art

Digital tape-recording remains a viable solution for the storage oflarge amounts of data in computer systems. Conventionally, at least twoapproaches are employed for recording digital information onto magneticrecording tape. One approach calls for moving a magnetic tape past arotating head structure that reads and writes user information fromdiscontinuous transverse tracks. Interactive servo systems are typicallyemployed to synchronize rotation of the head structure with travel ofthe tape. Another approach is to draw the tape across a non-rotatinghead at a considerable linear velocity. This approach is sometimesreferred to as linear “streaming” tape recording and playback.

Increased data storage capacity and retrieval performance is desired ofall commercially viable mass storage devices and media. In the case oflinear streaming tape recording, a popular trend is toward multi head,multi-channel fixed or servo (positioning) head structures with narrowedrecording gaps and data track widths so that many linear data tracks maybe achieved on a tape medium of a predetermined width, such as one-halfinch width tape. To increase the storage density for a given cartridgesize, the bits on the tape may be written to smaller areas and on aplurality of parallel longitudinal tracks. As more tracks are recordedon the tape, each track becomes increasingly narrow. As the tracksbecome more narrow, the tape becomes more susceptible to errors causedfrom the tape shifting up or down (often referred to as lateral tapemotion or “LTM”) in a direction perpendicular to the tape travel path asthe tape passes by the magnetic head. In order to maintain properalignment of the head with the data tracks on the tape, the tape isgenerally mechanically constrained to minimize lateral tape motion anddata retrieval errors.

Lateral tape motion is generally defined as the peak-to-peak distance ofthe undesirable movement (in-plane) of the tape perpendicular to itsprescribed longitudinal direction of motion past a read/write head.Lateral tape motion and the ability to compensate for and reduce lateraltape motion is a major limiting factor in determining the minimum widthof a track and the minimum spacing between tracks on the tape. Thus, aslateral tape motion is reduced, more tracks may be stored on the tapeand the storage capacity increases accordingly.

Tape substrates are also being made thinner to increase data storage fora given cartridge size. The thinner tape allows more tape to becontained within the same size diameter reel cartridges, e.g., acartridge about four inches square and one inch high for use with a fiveand one quarter inch tape drive. Increasing the tape within a givencartridge increases the data storage capacity of the cartridge. Thinnertapes, however, are generally less rigid making them more susceptible tolateral tape motion errors and damage or wear to the tape from the tapedrive assembly. For example, guides and rollers that may be used, atleast in part, to reduce lateral tape motion and define a tape paththrough a tape drive adjacent a read/write head may damage edge portionsof the tape.

One approach to minimize lateral tape motion tracking errors is toprovide a multi-roller tape guide structure within a tape drive, such asthe type described in commonly assigned U.S. Pat. No. 5,414,585,entitled “Rotating Tape Edge Guide,” the disclosure thereof beingincorporated herein by reference in its entirety. Such an approach mayprovide a reduction in both lateral tape motion and possible damage tothe tape during guiding.

The advent of new head technologies, however, such as magneto-resistiveread heads, and new higher coercivity recording media, data track widthshave become very small, and many additional data tracks may be definedon the tape. Unfortunately, lateral tape motion remains as a limitingfactor, and at certain data track width dimensions and data trackdensities, it is not possible to follow the tape accurately enough toprovide reliable performance during reading and writing operations.Further, as tape thickness is decreased tape edge damage and lateraltape motion become an increasingly greater problem.

Therefore, conventional systems have not been able to keep pace with theincreased data storage capacity desired for magnetic tape storage media,including increasingly narrow data tracks and thinner storage media. Aneed exists therefore for a device and method to reduce lateral tapemotion and reduce tape edge damage to potentially allow for increaseddata storage capabilities.

BRIEF SUMMARY OF THE INVENTION

In one example of one aspect of the invention, a single reel datastorage cartridge is provided. The single reel data storage cartridgeincludes a housing having an access window and a reel with storage tapewound thereon rotatably disposed within the housing. A guide surface isfurther disposed within the housing wherein the storage tape extendsfrom the reel to the guide surface before extending through the accesswindow, and the storage tape is adapted to be releasably attached to atake-up reel of a tape drive such that the storage tape may be removedfrom the housing through the access window to pass by a data transducerand wound on the take-up reel. The guide surface thereby increases thetape path from the reel to the access window and subsequent guidingelements within a tape drive to reduce the force imparted on the tapeedge during guiding.

According to another example of another aspect of the invention, a tapepath between a storage cartridge supply reel and a tape drive take-upreel is provided. The tape path extends from the supply reel housedwithin the cartridge and is guided within a tape drive adjacent a datatransducer before engaging the take-up reel in the tape drive. The tapepath is further guided by a guide surface within the storage cartridgehousing prior to engaging a first guiding element of the tape drive. Thedistance of the tape path between the supply reel within the cartridgeand the first guiding element of the tape drive is increased by theguide surface.

The present invention is better understood upon consideration of thedetailed description below in conjunction with the accompanying drawingsand claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a plan view of an exemplary magnetic tape drive andmagnetic tape cartridge;

FIG. 2 illustrates a cross-sectional view of an exemplary cartridgehaving an internal guide surface;

FIGS. 3-6 illustrate cross-sectional views of various exemplarycartridges having one or more internal guide surfaces;

FIGS. 7A-7C illustrate cross-sectional views of exemplary guidesurfaces; and

FIGS. 8A-8D illustrate top views of exemplary guide surfaces.

DETAILED DESCRIPTION OF THE INVENTION

The following description is presented to enable any person skilled inthe art to make and use the invention. Descriptions of specificmaterials, techniques, and applications are provided only as examples.Various modifications to the examples described herein will be readilyapparent to those skilled in the art, and the general principles definedherein may be applied to other examples and applications withoutdeparting from the spirit and scope of the invention. Thus, the presentinvention is not intended to be limited to the examples described andshown, but is to be accorded the scope consistent with the appendedclaims.

According to one example, a single reel storage cartridge housingmagnetic storage tape and having an internal guide surface is described.The storage cartridge includes at least one guide surface within thecartridge housing configured to increase the tape span or path lengthfrom the cartridge reel to a first guiding element located within a tapedrive. Increasing the tape span length between the cartridge reel andthe first guiding element may reduce the force required to guide thetape at the first guiding element. Reducing the guiding force on theedges of the tape at the first guiding element within the tape drivereduces the potential for tape edge damage and lateral tape motion.

The potential for tape edge damage is generally a function of the forceapplied to the tape edges. In particular, for a given tape thickness andmaterial, the guiding force applied to the tape edges will beproportional to the damage and wear to the tape edges. Further, theguiding force is generally inversely proportional to the path length ortape span length from the cartridge reel to the first guiding element ina tape drive. For example, the guiding force is generally proportionalto 1/L³, where L is the tape path length from where the tape leaves thecartridge reel and underlying wound tape to the first guiding elementwithin a tape drive. Therefore, the potential for tape edge damage maybe reduced by using one or more guide surfaces inside the cartridge reelto increase the path length, i.e., L, before the tape extends from thecartridge housing and engages a guiding element of a tape drive.

Referring initially to FIG. 1, an exemplary tape drive 10 is illustratedthat may be used with an exemplary cartridge 24 having one or moreinternal guide surfaces to increase the tape path and reduce thepotential for tape edge damage. Tape drive 10 includes a tape drivehousing 15, a data transducer, i.e., read and/or write head 16, atake-up reel 17, and a receiver 20. Tape drive 10 is used in conjunctionwith a cartridge 24 which houses a storage tape 28 on supply reel 26.Receiver slot 20 is configured to receive a suitable cartridge 24therein adjacent reel driver 18. Tape drive 10 may also include a doorand various mechanisms for receiving and ejecting cartridge 24. Whencartridge 24 is received in receiver slot 20 a buckler motor 46 or thelike may engage a cartridge leader and stream storage tape 28 along atape path within tape drive 10 passing read/write head 16 and ontotake-up reel 17. The tape path may include various tape guides 39,rollers 38, one or more read/write heads 16, and the like before beingwound upon take-up reel 17.

Tape drive 10 is typically installed within or associated with acomputer (not shown) or computer network. Additionally, tape drive 10may be used as part of an automated tape library having a plurality oftape cartridges and a robotic transfer mechanism to transport cartridgesto one or more tape drives. An exemplary storage library is described inU.S. Pat. No. 5,760,995, entitled “MULTI-DRIVE, MULTI-MAGAZINE MASSSTORAGE AND RETRIEVAL UNIT FOR TAPE CARTRIDGES,” which is herebyincorporated by reference in its entirety.

Cartridge 24 generally includes a substantially rectangular cartridgehousing which encloses cartridge reel 26 and storage tape 28. Cartridge24 may further include a cartridge door to protect storage tape 28therein and a cartridge leader (not shown), which is exposed when thedoor is open. Storage tape 28 stores information in a form, e.g.,digital, that may be subsequently retrieved if desired. Storage tape 28may be approximately one-half inch in width, but larger and smallerwidths are contemplated, e.g., 4-8 mm. Storage tape 28 may have athickness of approximately 0.5 mils (0.0005 inch) or thinner. Typically,storage tape 28 includes a storage surface on one side of storage tape28 that may be divided into a plurality of parallel tracks along thelength of storage tape 28. Alternatively, the data may be recorded indiagonal strips across storage tape 28.

It should be understood that the exemplary cartridges having an internalguide surface described herein may be used with various tape drives notexplicitly shown or described. Additionally, various other features of atape drive may be included, for example, various buckler systems,rollers, tape guides, receiving mechanisms, dampers, and the like may beused. A detailed description of various components of a tape drivesystem that may be used is provided in U.S. Pat. No. 6,095,445, entitled“CARTRIDGE BUCKLER FOR A TAPE DRIVE,” which is incorporated herein byreference in its entirety. A representative magnetic tape drive forwhich an exemplary storage cartridge may be used is sold by QuantumCorporation under the trademark SDLT™ 320.

With reference now to FIG. 2, a schematic cross-sectional view of anexemplary cartridge 224 having an internal guide surface 220 is shownwithin a tape drive 210 having a first guiding element 238. Cartridge224 further includes cartridge reel 212 having storage tape 202 woundthereon, and extending to guide surface 220 and access window 214.

Generally, storage tape 202 is wrapped between two flanges of reel 212that are separated by a distance slightly greater than the width ofstorage tape 202. For a variety of reasons, storage tape 202 may beoffset and have a force imparted to the tape edge at the first guidingelement 238 located within tape drive 210. For example, as storage tape202 is wound onto reel 212 storage tape 202 may not stack evenly on reel212 such that as storage tape 202 unwinds storage tape 202 is offsetfrom the first guiding element 238. Further, reel 212 itself may beoffset from first guiding element 238. If the guiding force is too greatat the first guiding element 238 the force may cause damage to the edgesof storage tape 202. Damages to the edges of storage tape 202 mayincrease the propensity for undesirable lateral tape motion duringoperation.

In this example, guide surface 220 is positioned such that storage tape202 is lifted from the tape wound on reel 212 at point A as reel 212rotates counterclockwise. Tape 202 reengages reel 212 and underlyingtape wound thereon after engaging guide surface 220 in the lower righthand side of reel 212 of FIG. 2 before disengaging again at point B.During operation, tape 202 may “float” on a thin layer of air trappedbetween tape 202 and underlying wound tape as the tape reengages withreel 212 between the guide surface 220 and point B of reel 212. The thinlayer of air reduces the friction between tape 202 and underlying woundtape and allows tape 202 to be guided by guiding element 238 over thedistance from point A to point C.

A tape span or path length for which tape 202 may be guided includes thedistance from where storage tape 202 initially leaves reel 212 at pointA to where storage tape 202 engages the first guiding element 238 oftape drive 210. The tape path extends generally from point A, where thetape 202 is lifted from reel 212, around guide surface 220 and reel 212to point B, where tape 202 extends through access window 214 to guidingelement 238 at point C. The addition of guide surface 220 guidingstorage tape 202 away from reel 212 at point A increases the path lengthfrom B to C to further include the distance from point A, around guidesurface 220, and to point B. For example, if cartridge 224 does notinclude guide surface 220, the tape path between reel 212 and guidingelement 238 would extend generally from point B to point C. The additionof guide surface 220 increases the tape path by more than one-half ofthe circumference of reel 212.

The force acting on the edge of storage tape 202 is inverselyproportional to the path length between reel 212 and first guidingelement 238. Therefore, the increased tape span or tape path distance byincluding the internal guide surface 220 may reduce the force and damageto the edge of tape 202 when guiding tape 202 to a desired path withinthe tape drive 210 for reading and/or writing.

Guide surface 220 is shown in this example as a cylindrical element.Guide surface 220, however, may include a variety of different shapeddevices and contoured surfaces. For example, it is contemplated thatguide surface 220 may include a stationary pin or rod, roller, contouredsurface, and the like. Further, the diameter and position of guidesurface 220 may vary within cartridge housing 210 depending on theparticular application, desired dimensions of cartridge 224, and desiredtape path length between guide surface 220 and access window 214.

Cartridge housing 224 is preferably sized to be received by a typicaltape drive, such as for use within a 5.25 inch (130 mm) form factordrive, a 3.5 inch (90 mm) form factor drive, or other useful size. Anaccess window 214 is included on one side to allow access to storagetape 202. Access window 214 may be covered by a door (not shown) thatmay be selectively opened when accessing storage tape 202.

Cartridge 224 may include various shapes and designs such as square,rectangular, circular, and the like. Cartridge 224 may further includevarious formed indentations, protrusions, notches, and the like forutility or aesthetics. In one example, cartridge 224 includes twosections, for example, a base section and a cover section, which matetogether to house storage tape 202. It will be recognized by thoseskilled in the art that numerous configurations and designs for thecartridge housing are possible.

The cartridge housing may be made of any suitable material, for exampleplastic and the like. The cartridge housing preferably includes a rigidmaterial to protect the enclosed reel and magnetic tape. Further, thecartridge housing may be manufactured by injection molding processes asare known in the art. The internal guide surface(s) may be comolded withthe housing or disposed in any suitable manner. Further, the guidesurfaces may include any suitable material such as plastics, lowfriction metals, ceramics, and the like.

FIGS. 3-7 illustrate various cross-sectional views of exemplarycartridges having one or more internal guide surfaces. In particular,FIG. 3 illustrates an exemplary cartridge 324 with a single guidesurface 320 disposed within cartridge 324 to increase the tape pathwithin cartridge 324 and to first guiding element 338. In this example,the guide surface 320 is positioned closer to access window 314 toincrease the tape path by greater than three-fourths of thecircumference of reel 312, i.e., from point A around guide surface 320and underlying wound tape on reel 312 to point B.

Guide surface 320 includes a roller in this example that is rotatablymounted within the housing of cartridge 324. This allows guide surface320 to rotate as tape 302 passes by, which may reduce the frictionalforce and potential wear and damage to tape 302 during rotation of reel312. Alternatively, a stationary guide surface might be desired tofrictionally dampen lateral tape motion as tape 302 is unwound from reel312.

FIG. 4 illustrates another exemplary cartridge 424. In this example,cartridge 424 includes two internal guide surfaces. A first guidesurface 420 may be included to lift tape 402 from reel 412 at point A.Guide surface 420 includes a contoured surface configured to reduce thewrap angle created between tape 402 and the leading/trailing edges ofguide surface 420. Reducing the wrap angle may reduce potential damageand wear to tape 402 as tape 402 passes guide surface 420. The lowerprofile guide surface 420 may further allow for a smaller cartridge 424housing because it may be disposed in close proximity to reel 412.

Further, cartridge 424 includes a second guide surface 421 positioned toguide and increase the path length of tape 402. Guide surface 421 mayinclude a fixed pin, rotating surface, or contoured surface depending onthe particular application. It should be recognized that cartridge 424may include either guide surface 420 or 421 alone or in combination withvarious other guide surfaces. Additionally, at slower streaming speeds,tape 402 may not float sufficiently when reengaging reel 412 after firstguide surface 420, e.g., the air may squeeze out from tape 402 andunderlying tape on reel 412 before reaching point B. Lifting tape 402 asecond time reduces the time and distance that tape 402 reengages reel412 to reduce the friction when reengaging reel 412.

FIG. 5 illustrates another exemplary cartridge 524 having three guidesurfaces 520, 521, and 522 within the housing of cartridge 524. Guidesurfaces 520, 521, and 522 are configured within the housing ofcartridge 524 such that the tape path is increased from point A to pointC, but tape 502 does not reengage tape reel 512 before engaging firstguiding element 538. Guide surfaces 520, 521, and 522 may include anytype or shape of guide surface, and fewer or more guide surfaces may beused depending on the application, for example, only guide surface 522might be used. Cartridge 524 may be used in applications where tape 502reengaging reel 512 is undesirable.

FIG. 6 illustrates another exemplary cartridge 624 having a single guidesurface 620 within the housing. This example illustrates an internalguide surface 620 having a compact design and low wrap angle of tape 602with the guide surface 620. As shown, guide surface 620 may fit withinthe corner of the cartridge 624 housing adjacent reel 612. In thisinstance, the rectangular housing does not need to be enlarged toaccommodate guide surface 620. Further, guide surface 620 is shaped toreduce the wrap angle of tape 602 both as tape 602 approaches and exitsguide surface 620, i.e., when tape 602 is wound and unwound from reel612. It should be recognized of course that a cylindrical pin or rollershaped guide surface 620 may also be disposed in a corner of the housingof cartridge 624 and maintaining similar dimensions of cartridge 624.

FIGS. 7A-7C illustrate various side cross-sectional views of exemplarycylindrical shaped guide surfaces 720 a-c. The exemplary cylindricalguide surfaces 720 a-c may include stationary elements or rotatingelements. Further, the exemplary guide surfaces 720 a-c may include anysurface of revolution such as concave or convex guide surfaces as shownin FIGS. 7B and 7C to assist in guiding the storage tape and/or reducingpotential damage to the storage tape during operation.

FIGS. 8A-8D illustrate various top views of exemplary guide surfaces 820a-d. As illustrated the guide surfaces may include a variety of shapesand designs to create desired guide surfaces, wrap angles, and the like.The various guide surfaces 820 a-d may be used alone or in anycombination depending on the particular application. The various guidesurfaces may also be oriented in different configurations, include acompound radius surface, and the like to create different wrap angleswith the storage tape.

The above detailed description is provided to illustrate exemplaryembodiments and is not intended to be limiting. It will be apparent tothose skilled in the art that numerous modification and variationswithin the scope of the present invention are possible. Accordingly, thepresent invention is defined by the appended claims and should not belimited by the description herein.

1. A tape path between a storage cartridge supply reel and a tape drivetake-up reel, comprising: a tape path extending from a reel housedwithin a storage cartridge housing to a take-up reel of a tape drive,wherein the tape path is guided within the tape drive adjacent a datatransducer before engaging the take-up reel of the tape drive; the tapepath is guided by a guide surface within the storage cartridge housingprior to engaging a first guiding element of the tape drive, wherein theguide surface is positioned within the housing to guide the storage tapeaway from the reel and then back to reengage the reel before extendingto the access window.
 2. The tape path of claim 1, wherein the firstguiding element includes a guide roller in the tape drive.
 3. The tapepath of claim 1, wherein the first guiding element includes a stationaryguide in the tape drive.
 4. The tape path of claim 1, wherein the guidesurface includes a rotatable surface.
 5. The tape path of claim 1,wherein the guide surface includes a stationary surface.
 6. The tapepath of claim 5, wherein the guide surface is positioned within thehousing to guide the storage tape away from the reel and then back toreengage the reel before extending to the access window.
 7. The tapepath of claim 1, wherein the guide surface includes a contoured surface.8. The tape path of claim 1, further comprising: a second guide surfacedisposed within the housing, wherein the storage tape extends to thesecond guide surface before extending to the access window.
 9. The tapepath of claim 8, wherein the guide surface is positioned within thehousing to guide the storage tape away from the reel and then back toreengage the reel before extending to the access window.
 10. The tapepath of claim 8, wherein the guide surface includes a rotatable surface.11. The tape path of claim 8, wherein the guide surface includes astationary surface.
 12. The tape path of claim 1, wherein the tape pathis guided through only a single access window of the storage cartridgehousing for access by the data transducer.
 13. The tape path of claim 1,wherein the tape path is guided by only a single guide surface withinthe storage cartridge housing.
 14. A tape path between a storagecartridge supply reel and a tape drive take-up reel, comprising: a tapepath extending from a reel housed within a storage cartridge housing toa take-up reel of a tape drive, wherein the tape path is guided withinthe tape drive adjacent a data transducer before engaging the take-upreel of the tape drive; the tape path is guided by a guide surfacewithin the storage cartridge housing prior to engaging a first guidingelement of the tape drive, wherein the guide surface is positionedwithin the housing to guide the storage tape away from the reel and thenback to reengage the reel before extending to the access window; and adistance of the tape oath between the supply reel within the storagecartridge housing and the first guiding element of the tape drive isincreased by the guide surface.
 15. The tape path of claim 14, whereinwhen the reel is driven the storage tape becomes separated from the reelby a thin layer of air.
 16. The tape path of claim 14, wherein the guidesurface includes a rotatable surface.
 17. The tape path of claim 14,wherein the guide surface includes a stationary surface.
 18. The tapepath of claim 14, wherein the tape path is guided through only a singleaccess window of the storage cartridge housing for access by the datatransducer.
 19. The tape path of claim 14, wherein the tape path isguided by only a single guide surface within the storage cartridgehousing.